In vitro starch digestibility of buckwheat cultivars in comparison to wheat: The key role of starch molecular structure

•The in vitro digestibility of buckwheat starches was compared with wheat starches.•Amylose content has no relation with the digestibility of fully gelatinized starch.•High amount of branch with 13 < DP ≤ 24 decreased the C∞ of buckwheat starch.•24 < DP ≤ 36 lead to a slow digestion rate of buckwheat starch in initial phase.•Digestion rate in latter phase were positively correlated with βAp,2 of buckwheat.